Seals of the padlock type are widely used in the electrical utility industry to seal electric meters and in many other application. Such seals in common use comprise a plastic body having a pair of spaced apertures, and a straight wire shackle having reverse bent ends that are non-removably inserted into the apertures. Such seals are disclosed in U.S. Pat. Nos. 3,485,521 and 4,278,281.
However there are many applications in which seals of this type cannot be used, in some cases because of the thickness of the wire shackle, and in other cases, because the dimensions and configuration of the device to be sealed do not allow the bent end of the shackle to be inserted through the apertures in the device to be sealed.
Also, in some instances such devices have been removed without leaving evidence of tampering.